I walked the Kintyre Way earlier this year and took this guide with me, although I didn't need it and should have left it at home. The Kintyre Way has the best waymarking of any long distance path I have walked in the UK (though it could benefit from some directional arrows in places). The posts are bright blue and you really can't miss them. I also took the two OS maps but didn't need them; these would only be necessary for side trips.
The guide contains all the usual things: Essential details for planning, nature, terrain, stages, spurs (there are two), Scottish Access Code, dogs, where to look for accommodation, pronunciation (always find this useful), fitness, packing, local economy, whisky, habitats, wildlife and general background on Kintyre and the Isle of Gigha.
Each stage is then described in detail, although the directions would not be adequate without waymarks and it is not necessary to refer to the guide for directions; I never did. The only reason for reading the stage sections are for points of interest along or near the route like Skipness Castle and Sadell Abbey.
The main issue I have with these Rucksack Readers guides is their weight. Unless using a baggage service, walkers won't want to carry the guide for 80 odd miles because the weight of the book isn't worth it. The best way to use the guide is to read it in advance and make a note of anything important, including transferring the route to an OS map if necessary (the Kintyre Way is on the latest OS maps).
The fold-out map at the end of the guide while initially interesting was ultimately not much use and I hardly referred to it, except to judge distance and relative locations of settlements and main roads.
As for the route itself, I was blessed with a week of scorching hot weather at the end of May. It made the whole area look beautiful and the waters a bright clear blue. The photographs could have been taken somewhere tropical! The towns of Tarbert and Campbeltown felt remote but there is lots to see and do there.
The terrain however was a bit of a chore, which was disappointing and wouldn't make me hurry back on foot. Underfoot is about 75% tarmac or forest track, 15% rocky or sandy beach, 5% grass and 5% bog. Most frustrating of all was that well over half the route could be driven in a car; this is certainly not the case with routes like the West Highland Way.
There aren't many pubs on the route. This is important info and so gets its own paragraph.
Lastly some advice to those planning to walk the Kintyre Way. Try to allow for side trips to Arran and Gigha to make the most of your time there. It is possible to stay on Arran at the end of the first day, which many do as there is no accommodation at Claonaig. Also the gardens on Gigha are well worth a visit and it is more interesting to stay there than at Tayinloan. Check ferry times though to make sure you are not stranded!
The walkability of coastal sections on the route is influenced by the tides, in particular the section out of Carradale. Although this is mentioned in the guide, I don't feel it is given nearly enough emphasis. If you plan low tide for any part of the walk, make sure it is this section. Otherwise you'll be struggling to follow the route and be delayed scrambling over rocks, or will have to resort to yet more road or a bus ride.
A day in Campbeltown is also worth planning for, as there is lots to see and as the following (possibly last) day is very strenuous. Walking the road from Campbeltown to Machrihanish is for dedicated completists only, and I would only suggest walking all the final 21 miles in one day if you are very fit.
I don't rate the Kintyre Way as highly as the other Scottish walks, which is a shame as the area is beautiful, but the guide book is more than adequate.